Liquid hydrogen filling port

Abstract

The application discloses a liquid hydrogen filling interface, which is coaxially provided with a first bellow, an annular sealing seat, a second bellow and a second inner tube which are sequentially connected from left to right in a central through hole of a second shell, a second valve core is coaxially arranged in an axial channel formed by the four sequentially connected parts and can be axially moved, the left end of the first bellow is sealingly connected with the left end of the central hole of the second shell, and the right end of the second inner tube is sealingly connected with the right end of the second shell; the left end hole diameter of the second inner tube is smaller than the outer diameter of the second valve core, a second pressing ring is arranged at the right end of the second inner tube, a second spring is located in the second inner tube and is sleeved outside the second valve core, and the two ends of the second spring abut against the outer step of the second inner tube and the second pressing ring respectively; a third spring is arranged between the annular sealing seat and the second inner tube. The liquid hydrogen filling interface is used in cooperation with a liquid hydrogen filling device, can realize purging and vacuum heat insulation during the filling process, is simple to operate, effectively improves the liquid hydrogen filling efficiency, and can reduce the workload and intensity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of liquid hydrogen filling device, in particular, relates to a liquid hydrogen filling interface. BACKGROUND

[0002] The fossil energy crisis and the increasing seriousness of greenhouse effect, human beings cast their eyes on the development and use of new energy. For example, renewable energy such as wind energy, solar energy, hydrogen fuel as a kind of combustion product only water, high calorific value of green energy, the favor of all countries in the world. Compared with high pressure hydrogen, liquid hydrogen has the advantages of low pressure, high energy density, convenient storage and transportation. Therefore, liquid hydrogen has a broader application prospect in new energy vehicles.

[0003] Unlike LNG, the temperature of liquid hydrogen is only about 20K, which is easy to absorb heat and vaporize, and the explosion limit of hydrogen is 4%-74.2%, so the air in the filling pipe should be purged during the filling process, and the filling pipe should be insulated to prevent low temperature scalding.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, provide a liquid hydrogen filling interface, which is used in cooperation with a liquid hydrogen filling device, can realize purging and vacuum insulation during the filling process, and is easy to operate.

[0006] To solve the above technical problems, the basic idea of the technical scheme adopted by the present application is:

[0007] The liquid hydrogen filling interface comprises a second shell, a second inner tube, a second valve core, a second spring, a third spring, an annular sealing seat, a first bellows and a second bellows.

[0008] The first bellows, the annular sealing seat, the second bellows and the second inner tube are coaxially arranged in the center through hole of the second shell from left to right, the left end of the first bellows is sealingly connected with the left end of the center hole of the second shell, and the right end of the second inner tube is sealingly connected with the right end of the second shell; the second valve core is coaxially arranged in the axial channel formed by the first bellows, the annular sealing seat, the second bellows and the second inner tube and can move axially, the left end hole diameter of the second inner tube is smaller than the outer diameter of the second valve core, the right end of the second inner tube is provided with a second pressure ring, the second spring is located in the second inner tube and is sleeved outside the second valve core, and the two ends of the second spring abut against the outer step of the second inner tube and the second pressure ring respectively; the third spring is arranged between the annular sealing seat and the second inner tube.

[0009] Further, the second shell has three layers of inner, middle and outer layers, the outer layer is connected with the left end of the middle layer, the middle layer is connected with the right end of the inner layer, a second vacuum cavity is formed between the outer layer and the middle layer, and a left end open insertion cavity is formed between the middle layer and the inner layer.

[0010] Further, there is a gap between the second shell inner layer and the first bellow, the annular sealing seat, the second bellow and the second inner tube, and the right end of the second vacuum cavity is communicated with the gap.

[0011] Further, the sealing ring is arranged on the top wall of the insertion cavity.

[0012] Further, the sealing ring is arranged on the left side of the annular sealing seat.

[0013] Further, the second valve core comprises three sections, i.e., a left section, a middle section and a right section, the left section is a top rod, the middle section has a conical surface, the right section has an axial half-through hole, a second through hole is arranged on the wall of the half-through hole, and the middle section of the second valve core cooperates with the left end of the second inner tube to close or open the axial channel formed by the first bellow, the annular sealing seat, the second bellow and the second inner tube.

[0014] Further, the outer side of the second shell is provided with a spiral groove, the spiral groove extends rightwards along the axial direction of the second shell and circumferentially along the second shell, and a hook bend extending leftwards along the axial direction of the second shell is arranged on the middle and tail ends of the spiral groove.

[0015] Further, the left end of the top rod of the second valve core is located in the second shell.

[0016] Further, a plurality of second through holes are uniformly arranged on the wall of the half-through hole of the right section of the second valve core along the circumferential direction.

[0017] Further, the outer step of the second inner tube abutting against the second spring is located on the right side of the second through hole.

[0018] After the above technical scheme is adopted, the present application has the following beneficial effects compared with the prior art.

[0019] The liquid hydrogen filling interface comprises a second shell, a second inner tube, a second valve core, a second spring, a third spring, an annular sealing seat, a first bellow and a second bellow, the second shell is coaxially provided with the first bellow, the annular sealing seat, the second bellow and the second inner tube which are sequentially connected from left to right in the central through hole of the second shell, the left end of the first bellow is sealingly connected with the left end of the central hole of the second shell, and the right end of the second inner tube is sealingly connected with the right end of the second shell; the second valve core is coaxially arranged in the axial channel formed by the first bellow, the annular sealing seat, the second bellow and the second inner tube and can axially move, the left end hole diameter of the second inner tube is smaller than the outer diameter of the second valve core, the right end of the second inner tube is provided with a second pressing ring, the second spring is located in the second inner tube and is sleeved on the outside of the second valve core, and the two ends of the second spring abut against the outer step of the second inner tube and the second pressing ring, respectively; the third spring is arranged between the annular sealing seat and the second inner tube. The liquid hydrogen filling interface is used in cooperation with a liquid hydrogen filling device, can realize purging during filling and vacuum heat insulation, is easy to operate, effectively improves the liquid hydrogen filling efficiency, and reduces the training cost of operators and the actual operation workload.

[0020] The specific embodiments of the present application will be further described in details below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this application, serve to provide further understanding of the application, its construction and its explanation, and together with the description, explain the application. Obviously, the accompanying drawings described below are only some embodiments, and other drawings can be obtained by those skilled in the art without any creative effort. In the drawings:

[0022] Figure 1 is a semi-sectional schematic view of the liquid hydrogen filling interface of the present application;

[0023] Figure 2 is a structural schematic view of the liquid hydrogen filling interface of the present application;

[0024] Figure 3 is a semi-sectional schematic view of the liquid hydrogen filling device of the present application;

[0025] Figure 4 is a schematic view of the liquid hydrogen filling interface of the present application and the liquid hydrogen filling device;

[0026] Figure 5 is a schematic view of the liquid hydrogen filling interface of the present application and the liquid hydrogen filling device;

[0027] Figure 6 is a schematic view of the liquid hydrogen filling interface of the present application and the liquid hydrogen filling device.

[0028] In the drawings: 100, outer tube; 101, first inner tube; 102, first housing; 103, first vacuum cavity; 104, first spring; 105, first valve core; 106, first through hole; 107, first compression ring; 108, pin shaft; 109, purge channel; 110, handle; 111, filling channel; 200, second housing; 201, second inner tube; 202, second vacuum cavity; 203, annular sealing seat; 204, first bellows; 205, second bellows; 206, second valve core; 207, second compression ring; 208, second spring; 209, third spring; 210, second through hole; 211, sealing ring; 212, plug-in cavity; 213, rotation groove.

[0029] It should be noted that these drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0031] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] like Figure 1 , 2 As shown, the liquid hydrogen filling interface of the present invention includes a second housing 200, a second inner tube 201, a second valve core 206, a second spring 208, a third spring 209, an annular sealing seat 203, a first bellows 204, and a second bellows 205.

[0034] The second housing 200 has a first bellows 204, an annular sealing seat 203, a second bellows 205, and a second inner tube 201 arranged coaxially from left to right in the central through hole. The left end of the first bellows 204 is sealed to the left end of the central hole of the second housing 200, and the right end of the second inner tube 201 is sealed to the right end of the second housing 200.

[0035] The second valve core 206 is coaxially disposed in the axial channel formed by the first bellows 204, the annular sealing seat 203, the second bellows 205 and the second inner tube 201, and can move axially to close or open this axial channel.

[0036] The diameter of the left end of the second inner tube 201 is smaller than the outer diameter of the second valve core 206. A second pressure ring 207 is provided at the right end of the second inner tube 201. The second spring 208 is located in the second inner tube 201 and is sleeved on the outside of the second valve core 206. The two ends of the second spring 208 abut against the outer step of the second inner tube 201 and the second pressure ring 207, respectively.

[0037] The second spring 208 can be compressed to move the second spool 206 to the right when the second spool 206 is subjected to a rightward pressure, and the second spring 208 can restore the deformation to push the second spool 206 to move to the left when the second spool 206 is no longer subjected to the rightward pressure or the rightward pressure is reduced.

[0038] In the embodiment, the second spool 206 includes a left segment, a middle segment and a right segment. The left segment of the second spool 206 is a top rod, the middle segment has a tapered surface, and the right segment has an axial half-hole with a plurality of second through holes 210 uniformly arranged on the wall of the half-hole in the circumferential direction. The middle segment of the second spool 206 is in contact with the left end of the second inner tube 201 to close or open an axial passage formed by the first bellows 204, the annular sealing seat 203, the second bellows 205 and the second inner tube 201. The left end of the top rod of the second spool 206 is located in the second housing.

[0039] The outer step of the second inner tube 201 abutting against the second spring 208 is located to the right of the second through hole 210.

[0040] The third spring 209 is arranged between the annular sealing seat 203 and the second inner tube 201. The third spring 209 can be compressed to move the annular sealing seat 203 to the right when the annular sealing seat 203 is subjected to a rightward pressure, and the third spring 209 can restore the deformation to push the annular sealing seat 203 to move to the left when the annular sealing seat 203 is no longer subjected to the rightward pressure or the rightward pressure is reduced.

[0041] The first limiting ring is sleeved in the first bellows 204, and the left end of the first limiting ring is sealingly connected to the left end of the central hole of the second housing 200. The second limiting ring is sleeved in the second bellows 205, and the left end of the second limiting ring is connected to the annular sealing seat 203. When the annular sealing seat 203 moves to the right under the rightward pressure, the second limiting ring sleeved in the second bellows 205 moves to the right together. When the right end of the second limiting ring abuts against the second inner tube 201, the annular sealing seat 203 cannot move to the right any more, thereby preventing the second bellows 205 from being excessively compressed and damaged. When the annular sealing seat 203 is not subjected to the rightward pressure, the annular sealing seat 203 is subjected to the leftward pressure of the third spring 209. At this time, the annular sealing seat 203 is limited by the first limiting ring on the left side, thereby preventing the first bellows 204 from being excessively compressed.

[0042] The second housing 200 has an inner layer, a middle layer and an outer layer. The outer layer is connected to the left end of the middle layer, and the middle layer is connected to the right end of the inner layer, thereby forming a second vacuum cavity 202 between the outer layer and the middle layer, and a plug-in cavity 212 with an open left end between the middle layer and the inner layer. The sealing ring 211 is arranged on the top wall of the plug-in cavity 212. The sealing ring 211 is located on the left side of the annular sealing seat 203.

[0043] The second shell 200 has gaps between the inner layer and the first bellows 204, the annular sealing seat 203, the second bellows 205 and the second inner tube 201. The right end of the second vacuum cavity 202 communicates with the gaps.

[0044] The second shell 200 is provided with a spiral groove 213 extending axially rightward along the second shell 200 and circumferentially along the second shell 200. The spiral groove 213 is provided with a hook bend extending axially leftward at the middle and tail end of the spiral groove 213.

[0045] The liquid hydrogen filling interface is mounted on a container in need of adding liquid hydrogen, and the liquid hydrogen filling interface is connected and matched with the liquid hydrogen filling device to realize liquid hydrogen filling.

[0046] As shown in Figure 3 The liquid hydrogen filling device comprises an outer tube 100, a first shell 102, a first inner tube 101, a first valve core 105, a first spring 104 and a limiting device.

[0047] The first inner tube 101 is coaxially arranged in the outer tube 100, and the two are fixedly connected, and a gap is formed between the first inner tube 101 and the outer tube 100 to form a channel.

[0048] The outer tube 100 is a stepped tube, wherein the part with a large outer diameter contains an annular first vacuum cavity 103. The end section of the outer tube 100 away from the limiting device is a single-layer wall, and the rest is at least a double-layer wall, and the annular first vacuum cavity 103 is formed between the double-layer walls. The outer diameter of the single-layer wall of the outer tube 100 is smaller than the outer diameter of the rest. The first vacuum cavity 103 can reduce the contact between the two layers of the outer tube 100, further reducing heat leakage during liquid hydrogen filling.

[0049] An end section refers to a section including the end and extending a certain length to the other end. For example, the end section of the outer tube 100 away from the limiting device is a single-layer wall, that is, the section including the end of the outer tube 100 away from the limiting device and extending a certain length to the other end is a single-layer wall.

[0050] The end section of the first inner tube 101 away from the limiting device is a single-layer wall, and the rest is at least a double-layer wall with a gap between the double-layer walls.

[0051] The central through hole of the first inner tube 101 is a stepped hole, and the first valve core 105 is arranged in the central through hole of the first inner tube 101 and can move axially to close or open the central through hole of the first inner tube 101.

[0052] One end of the central through hole of the first inner tube 101 is provided with a limiting device to limit the first valve core 105 from being pulled out of the first inner tube 101 from this end. In this embodiment, the limiting device is a first pressing ring 107 which is coaxially fixed in the central through hole of the first inner tube 101, and the inner diameter of the first pressing ring 107 is smaller than the outer diameter of the adjacent end of the first valve core 105, so as to limit the first valve core 105 from being pulled out of the first inner tube 101 from this end.

[0053] The other end of the central through hole of the first inner tube 101 has a hole diameter smaller than the partial outer diameter of the first valve core 105 to form a limiting step to limit the first valve core 105 from being pulled out of the first inner tube 101 from this end. In this embodiment, the contact part between the outer periphery of the first valve core 105 and the limiting step of the central through hole of the first inner tube 101 is a tapered surface, and the small-diameter end of the tapered surface faces the limiting step.

[0054] The outer tube 100 contains the annular first vacuum cavity 103 from the axial position corresponding to the limiting step to one end of the outer tube 100.

[0055] The section of the first valve core 105 close to the limiting device has an axial half-through hole, and a plurality of first through holes 106 are uniformly arranged on the wall of the half-through hole in the circumferential direction; the first through holes 106 are located on the side of the limiting step close to the limiting device.

[0056] The first valve core 105 is sleeved with the first spring 104, one end of the first spring 104 abuts against the limiting device, and the other end abuts against the outer periphery step of the first valve core 105. The outer periphery step of the first valve core 105 abutting against the first spring 104 is located on the side of the first through hole 106 of the first valve core 105 close to the limiting device.

[0057] The first valve core 105 comprises a top rod which is located on the side away from the limiting device and extends axially along the first inner tube 101, and the outer diameter of the top rod is much smaller than the inner diameter of the central through hole of the first inner tube 101. The end of the top rod is located in the first inner tube 101.

[0058] The first housing 102 is coaxially fixed outside the outer tube 100, and the end of the first housing 102 away from the limiting device has an annular gap with an opening between the outer diameter of the outer tube 100 and the small-diameter part, the opening is away from the limiting device, and the annular gap has a certain length along the axial direction of the outer tube 100. The pin shaft 108 is arranged on the first housing 102 in the radial direction and extends into the annular gap. The handle 110 is arranged outside the first housing 102.

[0059] In operation, the liquid hydrogen filling device is connected with the liquid hydrogen filling interface to realize liquid hydrogen filling.

[0060] The liquid hydrogen filling device is connected with the liquid hydrogen filling interface, as shown in Figure 4As shown, the pin shaft 108 on the first shell 102 of the liquid hydrogen filling device is inserted into the spiral groove 213 provided outside the second shell 200 of the liquid hydrogen filling interface, the single-layer wall at the right end of the outer tube 100 of the liquid hydrogen filling device is inserted into the insertion cavity 212 of the liquid hydrogen filling interface, and the right end of the first inner tube 101 of the liquid hydrogen filling device is inserted into the center hole of the first bellows 204 of the liquid hydrogen filling interface. By rotating the handle 110 of the liquid hydrogen filling device, the pin shaft 108 on the first shell 102 of the liquid hydrogen filling device slides in the spiral groove 213 outside the second shell 200 of the liquid hydrogen filling interface, and the part of the liquid hydrogen filling device inserted into the liquid hydrogen filling interface gradually increases to achieve connection. In this process, the single-layer wall at the right end of the outer tube 100 of the liquid hydrogen filling device contacts the sealing ring 211 on the top wall of the insertion cavity 212 of the liquid hydrogen filling device to form the first seal.

[0061] Continue to rotate the handle 110 of the liquid hydrogen filling device, as shown in Figure 5 As shown, the top rod of the first valve core 105 of the liquid hydrogen filling device abuts against the top rod of the second valve core 206 of the liquid hydrogen filling interface. Since the pre-tightening force of the first spring 104 of the liquid hydrogen filling device is smaller than the pre-tightening force of the second spring 208 of the liquid hydrogen filling interface, the first valve core 105 of the liquid hydrogen filling device moves to the left and no longer contacts the limiting step of the center through-hole of the first inner tube 101, the first valve core 105 opens the center through-hole of the first inner tube 101, and the right end of the first inner tube 101 of the liquid hydrogen filling device does not contact the annular sealing seat 203 of the liquid hydrogen filling interface. Therefore, the filling channel 111 formed after the first valve core 105 opens the center through-hole of the first inner tube 101, the purge channel 109 formed by the gap between the first inner tube 101 and the outer tube 100, and the part of the axial channel located to the left of the part of the channel between the middle section of the second valve core 206 and the left end of the second inner tube 201, which are formed by the first bellows 204, the annular sealing seat 203, the second bellows 205, and the second inner tube 201 of the liquid hydrogen filling interface, are connected. At this time, the pin shaft 108 on the first shell 102 of the liquid hydrogen filling device slides into the middle hook of the spiral groove 213 outside the second shell 200 of the liquid hydrogen filling interface, so that the liquid hydrogen filling device and the liquid hydrogen filling interface are connected and cannot be separated, which is the initial connection state. By passing the hydrogen gas generated by the vaporization of liquid hydrogen in the liquid hydrogen filling station through the center through-hole of the first pressure ring 107 into the filling channel 111 of the liquid hydrogen filling device, the above-mentioned three connected channels can be purged by the hydrogen gas generated by the vaporization of liquid hydrogen in the liquid hydrogen filling station, so that the air in the above-mentioned three channels is excluded by the hydrogen gas, ensuring that air is not mixed during subsequent filling of liquid hydrogen.

[0062] Continue to rotate the handle 110 of the liquid hydrogen filling device, as shown in Figure 6As shown, in this process or the aforementioned preliminary connection state, the left end of the first spool 105 of the liquid hydrogen filling device abuts against the first pressure ring 107 and no longer moves to the left, so the second spool 206 of the liquid hydrogen filling interface moves to the right, the second spring 208 is compressed, the second spool 206 opens the axial channel formed by the first bellows 204, the annular sealing seat 203, the second bellows 205 and the second inner tube 201, the right end of the first inner tube 101 of the liquid hydrogen filling device abuts against the annular sealing seat 203 of the liquid hydrogen filling interface and pushes the annular sealing seat 203 to move to the right, at this time the third spring 209 is compressed, the first bellows 204 is stretched, and the second bellows 205 is compressed. Continue to rotate the handle 110 of the liquid hydrogen filling device until the pin shaft 108 on the first shell 102 of the liquid hydrogen filling device slides into the tail hook of the outer rotary groove 213 of the second shell 200 of the liquid hydrogen filling interface, at this time the right end of the first inner tube 101 of the liquid hydrogen filling device abuts against the annular sealing seat 203 of the liquid hydrogen filling interface to form a second seal. Then proceed to fill liquid hydrogen.

[0063] After the liquid hydrogen filling is completed, the handle 110 of the liquid hydrogen filling device is rotated in the opposite direction to restore to the preliminary connection state, so that the pin shaft 108 on the first shell 102 of the liquid hydrogen filling device slides into the middle hook of the outer rotary groove 213 of the second shell 200 of the liquid hydrogen filling interface, and the liquid hydrogen filling device is connected with the liquid hydrogen filling interface without being separated. Then a large amount of nitrogen gas is introduced into the filling channel 111 of the liquid hydrogen filling device from the central hole of the first pressure ring 107, and the residual liquid hydrogen in the liquid hydrogen filling device and the liquid hydrogen filling interface is purged by nitrogen gas. Then continue to rotate the handle 110 of the liquid hydrogen filling device in the opposite direction to separate the liquid hydrogen filling device from the liquid hydrogen filling interface.

[0064] The application discloses a liquid hydrogen filling interface, which comprises a second shell, a second inner tube, a second valve core, a second spring, a third spring, an annular sealing seat, a first bellows and a second bellows, a first bellows, an annular sealing seat, a second bellows and a second inner tube are coaxially arranged in the center through hole of the second shell from left to right in sequence, the left end of the first bellows is sealingly connected with the left end of the center hole of the second shell, and the right end of the second inner tube is sealingly connected with the right end of the second shell; the second valve core is coaxially arranged in an axial channel formed by the first bellows, the annular sealing seat, the second bellows and the second inner tube and can be axially moved, the left end hole diameter of the second inner tube is smaller than the outer diameter of the second valve core, a second pressing ring is arranged at the right end of the second inner tube, the second spring is located in the second inner tube and sleeved outside the second valve core, and the two ends of the second spring are respectively abutted against the outer step of the second inner tube and the second pressing ring; the third spring is arranged between the annular sealing seat and the second inner tube. When the liquid hydrogen filling interface is not connected with a liquid hydrogen filling device, the liquid hydrogen filling channel of the liquid hydrogen filling interface is closed, in the connecting process, the hydrogen flow channel of the liquid hydrogen filling device is first opened, the liquid hydrogen in the liquid hydrogen filling station is used to blow hydrogen gas, two seals are formed with the liquid hydrogen filling device to prevent liquid hydrogen from leaking, and the liquid hydrogen filling channel of the liquid hydrogen filling interface is further opened. The liquid hydrogen filling interface is used in cooperation with the liquid hydrogen filling device, can realize blowing and vacuum heat insulation in the filling process, the whole process is simple to operate, the liquid hydrogen filling efficiency is effectively improved, and the training cost of operators and the actual operation workload are reduced.

[0065] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application in any form. Although the present application has been disclosed as above with reference to the preferred embodiments, the present application is not intended to be limited to the embodiments, and any person skilled in the art can make some changes or modifications to the above-mentioned technical content without departing from the technical solution of the present application, and the equivalent embodiments with equivalent changes are equivalent. The embodiments in the above-mentioned embodiments can be further combined or replaced, but as long as the content of the technical solution of the present application is not deviated, any simple modification, equivalent change and modification of the above-mentioned embodiments according to the technical essence of the present application are still within the scope of the present application.

Claims

1. A liquid hydrogen filling connection, characterized in that: The second housing, the second inner tube, the second valve core, the second spring, the third spring, the annular sealing seat, the first bellows and the second bellows, The first bellows, the annular sealing seat, the second bellows and the second inner tube are coaxially arranged in the second housing central through hole from left to right, The first bellows left end is sealingly connected with the second housing central hole left end, and the second inner tube right end is sealingly connected with the second housing right end; The second valve core is coaxially arranged in the axial channel formed by the first bellows, the annular sealing seat, the second bellows and the second inner tube and can be axially moved, The second valve core includes left, middle and right sections, the left section is a top rod, the middle section has a tapered surface, and the right section has an axial half-through hole, a second through hole is arranged on the half-through hole wall, and the middle section cooperates with the second inner tube left end to close or open the axial channel formed by the first bellows, the annular sealing seat, the second bellows and the second inner tube; The second inner tube left end hole diameter is smaller than the second valve core partial outer diameter, the second inner tube right end is provided with a second pressing ring, the second spring is located in the second inner tube and is sleeved outside the second valve core, and the two ends of the second spring respectively abut against the second valve core external step and the second pressing ring; The third spring is arranged between the annular sealing seat and the second inner tube; The second housing is provided with a rotation groove on the outside, the rotation groove extends along the axial direction of the second housing to the right and along the circumferential direction of the second housing, and the middle and tail ends of the rotation groove are provided with hook bends extending along the axial direction of the second housing to the left; In operation, the liquid hydrogen filling device is connected with the liquid hydrogen filling interface to realize liquid hydrogen filling, the liquid hydrogen filling device includes an outer tube, a first housing, a first inner tube, a first valve core, a first spring and a limiting device, the first valve core is sleeved with the first spring, one end of the first spring abuts against the limiting device, and the other end abuts against the first valve core peripheral step, When the liquid hydrogen filling device is connected with the liquid hydrogen filling interface, the pin shaft on the first housing is inserted into the rotation groove, and in the process of connection, the top rod of the first valve core abuts against the top rod of the second valve core, because the pre-tightening force of the first spring is smaller than that of the second spring, the first valve core moves to the left first, and the central through hole of the first inner tube is opened to form a filling channel, when the pin shaft slides into the middle hook bend of the rotation groove, the liquid hydrogen filling device is connected with the liquid hydrogen filling interface and cannot be separated, which is a primary connection state, at this time, the filling channel is opened, and the axial channel is closed, so that the hydrogen gas generated by the vaporization of the liquid hydrogen in the liquid hydrogen filling station is blown from the filling channel, and air is not mixed into the liquid hydrogen in subsequent liquid hydrogen filling, and then the second valve core opens the axial channel.

2. The liquid hydrogen fuelling interface of claim 1, wherein: The second housing has inner, middle and outer layers, the outer layer is connected with the left end of the middle layer, the middle layer is connected with the right end of the inner layer, a second vacuum cavity is formed between the outer layer and the middle layer, and a left-end-opened plug-in cavity is formed between the middle layer and the inner layer.

3. The liquid hydrogen fuelling interface of claim 2, wherein: There are gaps between the second housing inner layer and the first bellows, the annular sealing seat, the second bellows and the second inner tube, and the right end of the second vacuum cavity communicates with the above-mentioned gaps.

4. The liquid hydrogen fuelling interface of claim 2, wherein: A sealing ring is arranged on the top wall of the plug-in cavity.

5. The liquid hydrogen fuelling interface of claim 4, wherein: The sealing ring is located on the left side of the annular sealing seat.

6. The liquid hydrogen fuelling interface of claim 5, wherein: The top rod left end of the second valve core is located in the second housing.

7. The liquid hydrogen fuelling interface of claim 5, wherein: Multiple second through holes are uniformly arranged on the half-through hole wall of the second valve core right section along the circumferential direction.

8. The liquid hydrogen fuelling interface of claim 5, wherein: The second valve core external step abutting against the second spring is located on the right side of the second through hole.

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